In the past year two studies have been completed. The first has further characterized the distribution of BPH in the BLSA men. The probability of eventual surgery for BPH increases with increasing age and with the presence of an enlarged prostate and obstructive symptoms. The age specific prevalence of clinically diagnosed BPH agree closely with the age- specific autopsy prevalency of pathologically defined BPH. A second study examined prostate specific antigen as a marker of prostatic cancer. Longitudinal analyses demonstrated a significant age adjusted rate of change in PSA between subjects with prostate cancer, BPH and controls. At a time when PSA did not differ between BPH and prostate cancer subjects (5 years before diagnosis), rate of change in PSA was significantly greater in subjects with prostate cancer. The findings suggest that rate of change in PSA may be a sensitive and specific early marker for the development of prostate cancer.